Production of colored photographic images



Patented May 11, 1943 1 UNITED STATES PATENT OFFICE 2,318,818 PRODUCTION OF COLORED PHOTOGRAPHIC IMAGES Alan Gilbert Tull, Purley, England, assignor to Latta Syndicate Limited, London, England, a British company N Drawing. Application April 3, 1941, Serial No.

386,744. In Great Britain April 4, 194-0 8 Claims.

The present invention relates to the production of colored photographic images and it has for its principal object to provide a method of improving or modifying the characteristics of images containing a dye which gives the desired color and which mordants to that image or said con- "version product.

The present invention is applicable to a chemi cally toned image either forming a monochrome filloduigd blyi chemical toning processes, that is picture or forming one of the component color ose w oh the silver of a developed image records of a multi-color photographic picture, or the residual halide after such development, and the invention will be first described as apis I:fonverted directly or indirectly to a metallic plied to the toning of a single color picture, It nd, in general a colored salt. is assumed that as a result of the preceding In my co-pending application Serial No. 10 processing there is in the layerasilver salt image 378,301, filed February 10, 1941, a method of prowhich is preferably silver ferrocyanide or another clucing reversed chemically toned images from I metal salt image produced from said silver ferrot he regiciiuai harlliide of a silver halide emuision is cyan debv e al toning p o e SOmefOf escr e in w ch a silver ferrocyanide is first said images have been found to mordants or produced which is converted to various metal certain dyest f nd c ordi y O feature of Salt images such as Prussian blue or uranium the present invention consists in the dye-toning ferlrzlitgyan ide In my co-pending application seof such a metallic salt image directly with an r a o. 3 8,302, filed February 10', 1941, a process appropriate dye which mordants thereto. of producing multi-color records by producing It has been found however that a wider choice chemically toned images at different depths of a 0f dye 0 dye-toning i Possible if themor- 1silver!1i hallide 1 emulsionlllayer or layers is described 'dantlconslists 0; 2130 fie gy 1 gl One Of 1: n w c a russ an ue image is formed in a doube sa s. uc znc errocyan e may e surface layer or stratum while there is a red p d d y from the Silver ferrocyfilnide y image of a uranium ferrocyanide below that. In treatment in a zinc salt solution or if the silver 3:! cfgp gldigg a i a liceuon Serial No. 384,180 filed ferrocyanid has t er; preli g g g e arc 1 1 1, e production of a three colorinto some 0 er me errocyan e, rea men in record is described in which a uranium ferroa zinc salt solution will in e e Convert that cyanide image is formed in a middle layer. In salt into zinc ferrocyanide owing to the extremeall theseprocesses it may be found that a chemi- 1y low solubility thereof. This salt has been found cally toned image has not the desired spectral to be a particularly eflicient mordant for a large absorptions or that the image obtained is not sufnumber of basic dyestufisficiently permanent. Thus inthe particular case AS explained in y aid lo-P applicatlon of a uranium ferroeyanide image, the color of the serial 378302 0 Pictures y be image is not altogether satisfactory if the image D PQd 1n ye photogr p material is to form the magenta component of the three containing intermediate images such as silver color picture while, as described in said co-pendfermcyamde, by means of 1 mixed toning bath ing application Serial No. 384,180 it may in some of Whlch one of the components 15 Preferably cases be desired to havea yellow image in that ferric Salt producing an'iimage Prussian blue layer, and a more specific object of the invention In surface layer and another component is a is to modify or improve the color of such a 40 uranium salt producing an image of uranium nium ferrocyanide image to render 'it more suitferrqcyamde.below the Prussian blue image A particularly important advantage of the present able as the red, or more correctly magenta, image i nvention Is that it enables saiduranium ferroof the three color picture, although the invention c anme ima t b arm n r h 11 Convert d is qually applicable to the red image of a two y ge o e p yo w o y e color 1 t A f th f h 1 into a dye-toned image which as explained in co. c er 5 e invent pending application Serial No. 384,180 may be is to enabl? a yellow image to be prodluced in either magenta or yellow according to the charthe layer m which the uranium ferrocyamde acteristics of the material. This aspect of the image is first formed. The present invention also invention is based on the discovery that when e le she 0010f con l rg t )1 ateolored image to images consisting of Prussianblue and uranium 8 v e as xp a n r Il ferrocyanlde are treated in a solution of a zinc In accOrdance with h Present invention a salt, the Prussian blue image is substantially unchemically toned image or a conversion product affected while the uranium ferrocyanide is conderived therefrom is toned in a dye toning bath verted into zinc ferrocyanidewhich may then be toned for instance with Rhodamine G (Rowe veloper containing a silver solvent such as thiocyanate, the material is treated in a conversion bath as described in said co-pending application Serial No. 378,301 to produce in all layers reversed deposits of a silver ferrocyanide, after which the material is'treated in a mixed toning bath as described in said co-pending application Serial No. 878.302 to form a Prussian blue image in the outer layer followed by a uranium ferrocyanide image in the middle layer; a colored image being formed in the lower layer by selective destruction of the diflused dyestufi therein at any suitable stage in the operations. The uranium ferrocyanide image may not be of the desired magenta color and/or it may be desired to modify the color contrast thereof and in accord- .ance with the present invention the uranium ferrocyanide image in the middle layer is converted into zinc ferrocyanide by treating the material for instance in the following bath:

'Cc. Oxalic acid, 5% 5 Zinc sulphate, 10% solution. 5 Water to 20 The material is then washed for 10 minutes and thereupon or at some later stage, treated in 'a suitable dye bath. For magenta such a dye bath may consist of Rhodamine G (Rowe color index No. 750) containing sufllcient acetic acid to bring the strength of the latter to 1%. The

image by reaction with the uranium ferrocyanide; and dye toning with a dye which mordants to said mordant image. l

2. A method of producing a colored photographic image, which comprises producing a uranium ferrocyanide image; treating said image in a solution containing a zinc saltand oxalic acid to form a zinc salt mordant image by reaction with the uranium ferrocyanide; and dye toning said mordant image, in a bath containing a dye which mordants to said mordant image.

3. A method of producing a colored photographic image, which comprises producing a uranium ferrocyanide image; and treating said image in a bath containing a zinc salt which is capable of producing a zinc salt mordant image by reaction with the uranium ferrocyanide, and a dye capable of being mordanted to said mordant image.

4. A method of producing multi-color photographic images in a multi-layer photographic material, which comprises the steps of producing chemically toned images in at least some of said layers, or which one image consists of, uranium ferrocyanide; bathing the material in a solution containing a zine salt to form a mordant image from said uranium ferrocyanide, the images present in the other layers being such as to be unaffected by said zinc salt bath: and dye toning with a bath containing a dye capable of mordanting to said mordant image.

5. A method of producing multi-,color photographic images in a multi-layer photographic material, comprising forming silver ferrocyanide images in said layers, treating in a mix'edtoning bath containing a ferric salt and a uranium salt to form a Prussian blue image in the outer layer and a uranium ferrocyanide image in the following layer, treating in a zinc salt bath to convert material is then washed until the high lights are clear, acidulated water being used if necessary. If a yellow image should be desired in the middle 1 layer Rhodamine may be replaced by Auramine whlcha developed silver image is bleached to a silversalt image and a conversion product derived therefrom is treated in a-dye toning bath.

It should be noted that the zinc sulphate conversion bath given-above is without effect on the Prussian blue image in the top layer aftr the latter has been formed while, further, the dye baths given have no eiiect on the Pmssian' blue image. that is to say thedye does not become mordanted to the image deposit in that layer, enabling the color of the image in the under layer to be corrected without aflecting the color in the top layer.

The procedure given herein enables a color positive or negative to be produced in a verysimple manner and of satisfactory color properties.

I claim:

the uranium ferrocyanide into a zinc salt mordant and dye toning the said mordant.

6. A method of producing multi-color photographic images in a photographic material having three superimposed photographic silver halide layers comprising producing silver ferrocyanide images in said layers surrounded by a complementary deposit unaffected by the further processing, treating in a mixed toning bath containing a ferric salt and a uranium salt to form a Prussian blue image in the surface layer and a uranium ferrocyanide image in the following layer, treating in a zinc salt bath to convert the uranium ferrocyanide into a zinc salt mordant,

'dye toning the latter and at any appropriate stage forming a color image in the third layer.

7.. A method of producing multi-color photographic images in a photographic material having three superimposed photographic silver halide layers comprising exposing such'material to produce latent images in the three layers, developing such latent images, converting the residual halide in such layers in a solution containing a conversion reagent and a complex-forming substance to form a silver ferrocyanide, treating the material in a mixed toning bath containing a ferric salt and a uranium salt to form a Prussian blue, image in the surface layer and a uranium ferrocyanide image in the following layer, coni verting the uranium ferrocya'nide image into a l. A method of producing a colored photographic image, which comprises producing a uranium ferrocyanide image: bathing said image in a zincsalt bath to form a zinc salt mordant zinc salt mordant, dye toning the latter and at any appropriate stage producing a color image Y in the third layer.

ing three superimposed photographic silver ;hal-'- ide layers comprising eirposing such material to A ferrocyanide image in the following layer. con- 7 vetting the uranium i'errocyanide image into a v zinc salt mordant, dye toning the latter and at any appropriate stage producing acolor image in 5 the third layer.

ALAN GILBERT TUIL. 

